Sulfhemoglobin and sulfmyoglobin are two unusual nonfunctional forms of the native globins found in blood and tissue. They may also be formed in vitro under controlled conditions. Past research has shown that the sulfglobins are produced by the covalent addition of some sulfur containing moiety to the heme prosthetic group of the native globins. This project will determine the structure of these unusual derivatives. The modified heme will be isolated and stabilized by choice of extraction conditions or by conversion to a more stable derivative that retains a record of the original modification. The isolated heme will be characterized by proton nuclear magnetic resonance, optical, infra-red spectroscopy, and mass spectrometry to determine its structure. In parallel experiments, the solution structure of the whole protein sulfmyoglovin will be determined by proton nuclear magnetic resonance.